Vehicle diagnostic method, and external diagnostic device

Abstract

In a vehicle diagnostic method and an external diagnostic device, sensor detection values acquired by communicating with an ECU are measured to determine whether the values are in a normal range while a vehicle is idling. After an engine is started, an operation to measure soundness is prohibited at least until the sensor detection values including the engine rotational frequency reach a threshold value region indicating the completion of the warm-up operation. The fluctuation state of the sensor detection values is displayed on an operation screen until the sensor detection values reach the threshold value region.

The invention claimed is: 
     
       1. A vehicle diagnostic method for diagnosing a vehicle by an external diagnostic apparatus acquiring detected sensor values of the vehicle from the vehicle via data communication between an electronic control unit mounted on the vehicle and the external diagnostic apparatus, wherein
 the detected sensor values include an engine rotational speed; and 
 the external diagnostic apparatus carries out:
 an idling confirming step of measuring whether or not the engine rotational speed is within a normal range for the vehicle that is idling; 
 a health state measuring step of, when the vehicle is idling, measuring whether the detected sensor values acquired via communication with the electronic control unit are within normal ranges or not; 
 a measurement inhibiting step of inhibiting the measurement of the health state measuring step after an engine has started and during a period until the detected sensor values including at least the engine rotational speed reach threshold value regions indicating completion of warming-up of the vehicle, in which the vehicle can be judged as being idling; and 
 a varying state display step of displaying varying states of the detected sensor values on an operating screen during a period until the detected sensor values at which the measurement is inhibited reach the threshold value regions. 
 
 
     
     
       2. The vehicle diagnostic method according to  claim 1 , comprising:
 displaying, on the operating screen, a first start button for giving an instruction to start the measurement of the health state measuring step; 
 displaying the first start button as inactive so as to be non-selectable during the measurement inhibiting step; 
 displaying the first start button as active so as to be selectable after the measurement inhibiting step has been ended; and 
 displaying the varying states of the detected sensor values together with the first start button that is displayed as inactive. 
 
     
     
       3. The vehicle diagnostic method according to  claim 1 , wherein the detected sensor values include a coolant water temperature of the engine in addition to the engine rotational speed; and
 the varying state display step displays, on the operating screen, the varying states of the engine rotational speed and the coolant water temperature as animation images. 
 
     
     
       4. The vehicle diagnostic method according to  claim 3 , wherein when the external diagnostic apparatus is turned on, the external diagnostic apparatus acquires the detected sensor values including the engine rotational speed and the coolant water temperature regardless of whether the engine has started or not. 
     
     
       5. An external diagnostic apparatus for diagnosing a vehicle by acquiring detected sensor values of the vehicle through an electronic control unit mounted on the vehicle via data communication with the electronic control unit from outside of the vehicle, wherein
 the detected sensor values include an engine rotational speed; and 
 the external diagnostic apparatus comprises: 
 an idling confirming unit for measuring whether or not the engine rotational speed is within a normal range for the vehicle that is idling; 
 a health state measuring unit for, when the vehicle is idling, measuring whether the detected sensor values acquired via communication with the electronic control unit are within normal ranges or not; 
 a measurement inhibiting unit for inhibiting the measurement of the health state measuring unit during a period until the detected sensor values including at least the engine rotational speed reach threshold value regions indicating completion of warming-up of the vehicle, in which the vehicle can be judged as being idling; and 
 a varying state display unit for displaying varying states of the detected sensor values on an operating screen after an engine has started and during a period until the detected sensor values at which the measurement is inhibited reach the threshold value regions. 
 
     
     
       6. The external diagnostic apparatus according to  claim 5 , wherein a first start button for giving an instruction to start the measurement by the health state measuring unit displayed on the operating screen;
 the first start button is displayed as inactive so as to be non-selectable while the measurement by the health state measuring unit is being inhibited; 
 the first start button is displayed as active so as to be selectable when the inhibition of the measurement by the health state measuring unit is cancelled; and 
 the varying states of the detected sensor values are displayed together with the first start button that is displayed as inactive. 
 
     
     
       7. The external diagnostic apparatus according to  claim 5 , wherein the detected sensor values include a coolant water temperature of the engine in addition to the engine rotational speed; and
 the varying state display unit displays, on the operating screen, the varying states of the engine rotational speed and the coolant water temperature as animation images. 
 
     
     
       8. The external diagnostic apparatus according to  claim 7 , wherein when the external diagnostic apparatus is turned on, the external diagnostic apparatus acquires the detected sensor values including the engine rotational speed and the coolant water temperature regardless of whether the engine has started or not.